A Study On The Measurement & Modeling Of Elevator Rail Irregularities And The Properties Of Horizontal Vibration Of Cabin

As the guiding device, guide rails play an important role in the elevatorsystem. The irregularities of guide rails are the main exciting sources of thehorizontal vibration of a running elevator cabin. They have great influence onthe comfort and safety of the ride. The measurement and control for the railirregularities is an important work in assembling and inspecting an elevator.However, the current measuring methods generally have some drawbackssuch as low accuracy and efficiency. It is an imperative task to explore anaccurate and efficient method for measuring the irregularities of guide rails. Inaddition, the studies on the modeling of rail irregularities and horizontalvibration of the cabin, which is caused by the rail irregularities, are restricted toa large extent because of the lack of accurate and efficient measuring methods.This dissertation deals with the research on the measurement and modelingof the irregularities of guide rails, and on this basis studies the properties ofhorizontal vibration of the cabin caused by the rail irregularities. The main workdone and the creative ideas of this thesis are as follows.1. The development of a multi-parameter accurate and efficient systemfor measuring irregularities of the elevator railsIn the measuring system, a laser collimating technique based on positionsensitive detector (PSD) is used to measure the elevator rail errors, such as thestraightness and verticality errors in the whole range of guide rails, the localbowing, misalignment and step errors of guide rails. A differential measurementmethod with two inductive transducers is applied to determine the distancevariance between right and left guide rails. Several proximity switches aremounted to sense the positions of rail joints and brackets. In the process ofsoftware design, a powerful development platform is established by combiningLabVIEW and MATLAB with COM technique, which makes the systemintegrated and automatic.A new method for establishing a high precision laser vertical reference isproposed in the thesis. It is based on combining the auto-leveling and positionlocking techniques. With this method, a laser vertical reference with verticalityerror no more than two arc-seconds is set.A spatial 3-D nonlinear correction technique is put forward in the thesis tocorrect the nonlinearity errors of the PSD in long distance measurements. Also,an in situ automatic calibration device is developed.The experiments at lab and in situ show that the system can realize themulti-parameter measurement efficiently and accurately. For example, the timerequired for measuring a 50 m high guide rail is no more than 2 minutes, and thestandard deviation of measurement is less than 1 mm.The successful development of the measuring system provides a newefficient method to test the irregularities of guide rails in situ. It also offers agood basis for studying the modeling of irregularities and analyzing thehorizontal vibration of the cabin.2. Different probabilistic modeling approaches are explored tocharacterize the properties of two kinds of rail irregularities: localirregularities and overall irregularities.As for the probabilistic characterization of local irregularities of guide rails,appropriate methods for extracting local errors, such as step, misalignment andbowing of the rails, are put forward first. On this basis, the approaches forprobabilistic characterization are presented and the probabilistic models areestablished. The location and scale parameters, which reflect the assemblingquality of guide rails, are tested separately by utilizing the parametric ornonparametric statistical methods.In the analysis of the random characteristics of overall irregularities of therails, a model describing the overall irregularities in three different domains:amplitude domain, space domain and frequency domain is proposed based onthe theory of stochastic process. With establishment of an appropriate ARMAmodel for rail overall irregularities, their random characters are explored.Furthermore, a reasonable explanation of the physical background causing theseirregularities is given.These probabilistic models provide a set of reasonable theoretical analysismethods for evaluating the assembling qualities of guide rails and optimizingthe assembling schemes. In addition, they lay a theoretical basis for studying thehorizontal vibration of elevator cabin.3. A Study on the properties of horizontal vibration of elevator cabinunder different excitations caused by rail irregularities is carried out.A twelve-degrees-of-freedom nonlinear vibration model of the cabin-railcoupled dynamic system is established, and the numerical solution method usingthe state-space approach is described in detail. Based on this, the properties ofthe horizontal vibration of elevator cabin under different running conditions,such as the variation of the excitation intensity or the variation of velocity, areexplored. The reasons causing these properties are also studied in the thesis.The exploration of the properties of the horizontal vibration provides animportant theoretical foundation for determining the reasonable tolerances of theguide rails in manufacturing and assembling. In the mean time, it is helpful forimpelling the studies on optimization of the cabin structure and vibration controlof the cabin system.